An important aspect of image forming devices is the number of image sides that can be printed per minute, referred to as throughput. Usually, consumers want devices with a high throughput with good print quality and reliability.
FIG. 9 illustrates one embodiment of a prior art design illustrating an output section of a media path. Media sheets having an image formed on a first side move along the first media path 100. A diverter 102 illustrated in a first position noted by solid lines, is pivoted about point 103 to direct the media sheet to output rolls 104. If the imaging on the media sheet is complete, the output rolls 104 rotate in a first direction to discharge the media sheet from the device and into an output tray 105. If a second image is to be formed on the second side, the media rolls 104 rotate in the first direction until the trailing edge of the media sheet moves past the diverter 102. At this point, diverter 102 rotates about pivot 103 to a second position noted by dotted lines to close the first media path 100 and open the duplexer path 101. The output rolls 104 reverse and rotate in a second direction to drive the media sheet into the duplexer path 101 with the trailing edge now becoming the leading edge. This concept of introducing the media sheet into the duplexer path 101 is referred to as peek-a-boo duplexing because a leading section of the media sheet extends beyond the output rolls 104 and is visible from the exterior of the device. The sheet is then pulled back into the device when the output rolls 104 reverse to the second direction.
A second media sheet moving along the first media path must not interfere with the peek-a-boo duplexing. Therefore, the second sheet must either be paused in the first media path, or delayed to ensure it does not reach the diverter 102 until the previous sheet has cleared the area. This pausing and delay timing reduces the throughput of the device.